There's a saying -- or, there should be -- that you can judge a family film by the quality of its moppets. Child actors who are both cute and talented are a must, or else even the world's best story might end up on the scrap heap. Kirk Jones' Nanny McPhee has all the makings of classic material, then: a timeless story, a delightful cast of precocious children, a truly magical production design, and the cream of the crop among adult actors. (As one of those actors, Emma Thompson's presence isn't surprising, given that she adapted the screenplay from Christianna Brand's Nurse Matilda books.) Nanny McPhee contains the perfect blend of the whimsical and the macabre, in keeping with an age-old fairy-tale tradition. The story certainly features details that require a delicate touch, namely, a child who decapitates dolls with a guillotine, and a parent (Colin Firth) who works in a funeral parlor. But because Thompson and Jones keep the tone lightly absurd, these elements are not too scary for younger children. Nor is Thompson's creepy title character, whose methods walk the line between strictness and malevolence, and whose appearance is a makeup artist's dream of prosthetic nastiness. Of course, the story eventually boasts great warmth and compassion as its lessons unfold, particularly during the delicious conclusion -- "delicious" quite literally, as the characters become spattered with colorful gobs of cake icing. In addition to Firth, Thompson and the children (led by Love Actually's Thomas Sangster), two others deserve special mention: Kelly MacDonald as the Browns' darling scullery maid, and Angela Lansbury, hilarious as the stuffy old coot who dictates their fortunes. Thompson's character explains that when the children start wanting her rather than needing her, it's time for her to move on. Indeed, Nanny McPhee leaves its viewers wanting more, too.